Bicycles are often transported on vehicles. Numerous racks and devices have been devised to secure bicycles to vehicles during transport. One particularly common bicycle carrier utilizes a fork block mounted to a rack structure. The fork block has a skewer that clamps the front forks of a bicycle to secure the bicycle to the rack. The clamping pressure of the skewer on the forks is sufficient to stabilize the bicycle against tipping during travel. Typically, a wheel tray extends back from the fork block to support the rear wheel.
Fork block-type bicycle carriers present a number of design challenges. First, the fork block/skewer must grip the forks of the bicycle firmly enough to provide the needed stability. At the same time, it should be easy to secure the bicycle to or release it from the fork block, as well as easy to adjust to fit various bikes. In addition, the carrier should provide some way of securing the bicycle against theft when it is left unattended. More recently, bicycles have begun to incorporate front disk brakes. The disk brakes require calipers mounted to the front forks and such calipers often will not fit over the wheel tray on existing designs.